The interaction between the RING domains of Hdm2/HdmX E3 ligase is an effective therapeutic target for cancer treatment and prevention. We have already developed a bioactive cyclotide, MCo-52-2, able to inactivate Hdm2/HdmX E3 ligase activity in vitro and in vivo. The main goal of this proposal is to continue the development of this cyclotide as a single compound therapeutic agent using several mouse models of CRC.